Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262290AbUCCJpV (ORCPT ); Wed, 3 Mar 2004 04:45:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262320AbUCCJpV (ORCPT ); Wed, 3 Mar 2004 04:45:21 -0500 Received: from 10fwd.cistron-office.nl ([62.216.29.197]:60392 "EHLO smtp.cistron-office.nl") by vger.kernel.org with ESMTP id S262290AbUCCJpP (ORCPT ); Wed, 3 Mar 2004 04:45:15 -0500 Date: Wed, 3 Mar 2004 10:45:10 +0100 From: Miquel van Smoorenburg To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: Re: per-cpu blk_plug_list Message-ID: <20040303094509.GA8779@cistron.nl> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040302211309.500f43fb.akpm@osdl.org> X-NCC-RegID: nl.cistron User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 31 According to Andrew Morton: > And also having looked at Miquel's (currently slightly defective) > implementation of the any_congested() API for devicemapper: > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.4-rc1/2.6.4-rc1-mm1/broken-out/queue-congestion-dm-implementation.patch > > I am thinking that an appropriate way of solving the blk_run_queues() lock > contention problem is to nuke the global plug list altogther and make the > unplug function a method in struct backing_device_info. > > This is conceptually the appropriate place to put it - it is almost always > the case that when we run blk_run_queues() it is on behalf of an > address_space, and the few remaining case can be simply deleted - > mm/mempool.c is the last one I think. > > The implementation of backing_dev_info.unplug() would have to run the > unplug_fn of every queue which contributes to the top-level queue (the > thing which the address_space is sitting on top of). But then you need a pointer to the queue. In that case, you might as well put the congested_fn pointer in the request_queue too. Then you get something like https://www.redhat.com/archives/linux-lvm/2004-February/msg00203.html (though I'd replace "rw" with "bdi_bits" like in the current patch). Mike. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/